In Frank's piggy bank, there are only quarters and dimes. He has 37 coins, and has a total of
$5.50. How many quarters does he have?

12 quarters

Step-by-step explanation:

number of quarters x

number of dimes y

therefore, x + y = 37times 10 both sides 10x + 10y = 370equation 1

              0.25x + 0.1y = 5.5 times 100 both sides 25x + 10y = 550 equation 2

equation 2 minus equation 1 is 25x + 10y - 10x - 10y = 550 - 370 15x = 180 x = 12

there are 12 quarters

$9.89

step-by-step explanation:

9.90 = p x .06 x .25 (3/12 changed to a decimal)

9.90 = p x 0.015

9.90 - 0.015 = p

9.89 = p